Such torque converters have been known as startup elements in motor vehicle drive trains for a long time. Thus, a torque transferred by a drive unit through the converter housing to the pump is transferred to the turbine by means of an operating medium. Thus, a torque augmentation is produced by the stator, when a speed difference exists between the pump and the turbine (nT<nP), as the stator is supported through a freewheeling clutch in one direction of rotation against the housing and is rotatable in the other direction of rotation. For this purpose, the stator comprises radially extending blades disposed at regular intervals about the circumference of the stator, which control the flow of the operating medium. Thus, as a function of a speed based slippage between the pump and the turbine, the flow resistance of the operating fluid at the stator is supported at the housing through the freewheeling clutch, and a torque augmentation is generated at the output side of the torque converter, while the freewheeling clutch of the stator is overrun as a function of the changed flow conditions at high speed ratios.
Thus, it has become evident for some types of torque converters, that a torque curve of the torque converters determined over the pump speed is unbalanced in an undesirable manner, since e.g. an undesirable rise of the torque occurs at low drive speeds and at low to medium speed ratios.
Thus, it is the object of the invention to provide an improved torque curve without changing the other design parameters for adjusting the torque properties of the torque converter.